Method and device for acquisition of a geometric shape

• US 9,188,422 B2
• Filed: 03/06/2006
• Issued: 11/17/2015
• Est. Priority Date: 03/09/2005
• Status: Active Grant

• Current Assignee: Commissariat a L'Energie Atomique (AES Corporation)
• Original Assignee: Commissariat a L'Energie Atomique (AES Corporation)
• Inventors: David, Dominique, Sprynski, Nathalie
• Primary Examiner(s): Merouan, Abderrahim
• Application Number:
  US11/885,022
• Publication Number:
  US 20080211808A1
• Time in Patent Office: 3,543 Days
• Field of Search: 345419-427, 382141-152, 382/108, 382279-280, 700 91-306
• US Class Current: 1/1
• CPC Class Codes: G01B 7/287 using a plurality of fixed, simultaneously operating transducers G01B7/293 takes precedence
• CPC Class Codes: G06T 17/00 Three dimensional [3D] modelling, e.g. data description of 3D objects
• CPC Class Codes: G06T 17/005 Tree description, e.g. octree, quadtree
• CPC Class Codes: G06T 17/10 Constructive solid geometry [CSG] using solid primitives, e.g. cylinders, cubes
• CPC Class Codes: G06T 17/20 Finite element generation, e.g. wire-frame surface description, tesselation
• CPC Class Codes: G06T 19/00 Manipulating 3D models or images for computer graphics

Abstract

According to the invention, a set of sensors (4a) is placed on this shape (curve or surface), each sensor outputting signals representative of the orientation of the curve or the surface at the location of this sensor; a model of the curve or the surface is chosen; model parameters are determined from the signals; and the spatial distribution of the points on the geometric shape are determined using these parameters. The invention particularly applies to machining, joinery, masonry, and building domains.

Claims

1. A method for acquisition of a warped geometric shape, namely a warped curve or a warped surface, by determining the coordinates of the points on this warped curve or this warped surface, the method comprising:

placing a set of sensors on the warped geometric shape, the sensors being chosen among accelerometers and magnetometers, each accelerometer configured to sense inclination relative to the vertical direction and each magnetometer configured to sense inclination relative to magnetic north, each sensor being designed to output signals representative of the inclination of the local tangent to the curve or of the inclinations of the local tangent plane to the surface, at the location of the sensors with respect to the vertical direction in the case of accelerometers or with respect to the direction of the earth'"'"'s magnetic field in the case of magnetometers; and

modeling the curve or the surface by;

treating a distance between adjacent sensors as a straight line segment;

obtaining an inclination measurement from a sensor at an end of each segment, each said segment corresponding to a tangent of the shape at that segment; and

determining the spatial distribution of the points on the geometric shape by a step by step reconstruction of the straight line segments.

2. A method according to claim 1, in which the sensors are fixed to a support made of a deformable solid material capable of matching the shape to be acquired.

3. A method according to claim 2, in which the support forms a line.

4. A method according to claim 3, in which the support is flexible.

5. A method according to claim 2, in which the support forms a surface.

6. A method according to claim 5, in which the support is flexible.

7. A method according to claim 2, in which the support is flexible.

8. A method according to claim 1, in which the shape to be acquired has one or several maximum spatial frequencies and the number of sensors per unit length or unit area is equal to at least twice the value of the maximum frequency, and the curve or the surface is locally sampled using the sensors.

9. A method according to claim 1, in which the sensors are mechanically independent of each other, and the shape to be acquired is reconstructed step by step using signals output by the sensors.

10. A method according to claim 1, in which the shape of a curve or a surface that delimits an object is acquired.

11. A method according to claim 1, in which the intrinsic shape of the solid and deformable material itself is acquired.

12. A method according to claim 1, in which each sensor is also designed to determine the distance that separates it from nearby sensors, and in which the shape to be acquired is reconstructed step by step.

13. A device for acquisition of a warped geometric shape, namely a warped curve or a warped surface, the device comprising:

a set of sensors, the sensors being chosen among accelerometers and magnetometers, each accelerometer configured to sense inclination relative to the vertical direction and each magnetometer configured to sense inclination relative to magnetic north, each sensor being designed to output signals representative of the inclinations of the local tangent to the curve or of the inclination of the local tangent plane to the surface, at the location of the sensor with respect to the vertical direction in the case of accelerometers or with respect to the direction of the earth'"'"'s magnetic field in the case of magnetometers; and

electronic means for processing signals output by the sensors, the electronic means being designed to determine model parameters using a mathematical model of the curve or the surface, and to use these parameters to determine the spatial distribution of points on the geometric shape by;

treating a distance between adjacent sensors as a straight line segment;

obtaining an inclination measurement from a sensor at an end of each segment, each said segment corresponding to a tangent of the shape at that segment; and

determining the spatial distribution of the points on the geometric shape by a step by step reconstruction of the straight line segments.

14. A device according to claim 13, in which the sensors are fixed to a support made of a solid and deformable material, capable of matching the shape to be acquired.

15. A device according to claim 13, in which the sensors are mechanically independent of each other.

16. A method for acquisition of a warped geometric shape, namely a warped curve or a warped surface, by determining the coordinates of the points on this warped curve or this warped surface, the method comprising:

placing a set of sensors on the warped geometric shape, the sensors being chosen among accelerometers and magnetometers that are configured to sense inclination relative to a reference direction, each sensor being designed to output signals representative of the inclination of the local tangent to the curve or of the inclinations of the local tangent plane to the surface, at the location of the sensors with respect to the vertical direction in the case of accelerometers or with respect to the direction of the earth'"'"'s magnetic field in the case of magnetometers; and

modeling the curve or the surface by;

treating a distance between adjacent sensors as a straight line segment;

obtaining an inclination measurement from a sensor at end of each segment, each said segment corresponding to a tangent of the shape at that segment; and

determining the spatial distribution of the points on the geometric shape by a step by step reconstruction of the straight line segments.

17. A method according to claim 16, in which the sensors are fixed to a support made of a deformable solid material capable of matching the shape to be acquired.

18. A method according to claim 16, in which the shape to be acquired has one or several maximum spatial frequencies and the number of sensors per unit length or unit area is equal to at least twice the value of the maximum frequency, and the curve or the surface is locally sampled using the sensors.